1. Field of the Invention
The present invention relates to disc discrimination in an optical disc system capable of performing recording on and/or reproduction from a plurality of types of discs, and more particularly, to a method and apparatus for determining the type of a writable disc.
2. Description of the Related Art
FIG. 1 is a flowchart of a conventional disc discriminating method used in an optical disc system. The method is disclosed in Korean Patent Registration No. 176557 filed by the present applicant. Referring to FIG. 1, in operation 101, a maximum run length of an information signal read by rotating an optical disc at a constant velocity to control focusing is selected. In operation 102, the selected maximum run length signal is compared with a reference signal to determine whether the maximum run length signal is greater or less than the reference signal. If the maximum run length signal is greater than the reference signal, in operation 103, the optical disc is determined as a compact disc (CD), and in operation 104, a CD mode is set. If the maximum run length signal is less than the reference signal, in operation 105, the optical disc is determined as a digital versatile disc (DVD), and in operation 106, a DVD mode is set.
The conventional disc discriminating method discriminates whether an optical disc loaded in an optical disc system is a DVD or a CD. In case of a DVD, a track pitch and a pit length tend to be minimized to record a large amount of information in the same area. Thus, a signal detected from a pit has a high frequency in the DVD case and a detection time for the signal gets shorter. Therefore, a DVD can be distinguished from a CD using these characteristics. Such a signal can be detected from a pit when an optical spot passes on a recording surface of the optical disc due to focusing control. A pit signal having a maximum run length is selected from pit signals detected in such a way in order to minimize a discrimination error. A reference signal used for discriminating the type of disc is determined among maximum run length signals respectively detected from the DVD and the CD, and a signal read from a corresponding disc is compared with the reference signal to discriminate a DVD from a CD based on the comparison result.